The prevalence of dementia in the United States is declining among people over age 65, falling dramatically from 2000 to 2016, a RAND Corp. study says.
Nationwide, the age-adjusted prevalence of dementia fell to 8.5% of people over age 65 in 2016, down by nearly one-third from 12.2% of people over age 65 in 2000, according to the researchers.
Females are more likely to live with dementia, but the sex difference has narrowed, the study found.
Among men, the prevalence of dementia fell by 3.2 percentage points, from 10.2% to 7.0% over the 16-year span. The decrease was larger among women, down 3.9 percentage points, from 13.6% to 9.7% … the researchers cited “growing evidence” that age-adjusted dementia prevalence has been declining in developed countries, possibly due to rising levels of education, a reduction in smoking and better treatment of key cardiovascular risk factors such as high blood pressure…
(Péter Hudomiet, the study’s lead author) said it’s also possible that, given numerous studies being released on steps to take to avoid dementia, some of the decline may be attributed to people heeding such advice.
“It is also plausible that other behavior factors, such as smoking [cessation], cognitive activities, social activities, etc., played a role,” he said.
Trends in inequalities in the prevalence of dementia in the United States (PNAS). From the Abstract:
- This paper presents estimates of the prevalence of dementia in the United States from 2000 to 2016 by age, sex, race and ethnicity, education, and a measure of lifetime earnings, using data on 21,442 individuals aged 65 and older … We developed a longitudinal, latent-variable model of cognitive status, which we estimated using the Markov Chain Monte Carlo method … The age-adjusted prevalence of dementia decreased from 12.2% in 2000 (95% CI, 11.7 to 12.7%) to 8.5% in 2016 (7.9 to 9.1%) in the 65+ population, a statistically significant decline of 3.7 percentage points or 30.1%. Females are more likely to live with dementia, but the sex difference has narrowed. In the male subsample, we found a reduction in inequalities across education, earnings, and racial and ethnic groups; among females, those inequalities also declined, but less strongly. We observed a substantial increase in the level of education between 2000 and 2016 in the sample. This compositional change can explain, in a statistical sense, about 40% of the reduction in dementia prevalence among men and 20% among women, whereas compositional changes in the older population by age, race and ethnicity, and cardiovascular risk factors mattered less.